1. Technical Field
The embodiments described herein relate to a voltage measuring apparatus for a semiconductor integrated circuit and a voltage measuring system having the same. In particular, the present invention relates to a voltage measuring apparatus for a semiconductor integrated circuit that can measure a change in voltage level due to noise, and a voltage measuring system having the same.
2. Related Art
Conventional semiconductor integrated circuits are becoming more integrated, meaning an even larger number of components are being squeezed into even smaller areas within the semiconductor integrated circuit. As a result, noise or cross-talk can effect various elements and lines within the chip. For example, such noise can cause the external power source voltage level supplied to individual regions of the semiconductor integrated circuit can change. Such variations in the power source voltage can cause performance issues and even device failures. Despite such adverse effect, a technology that measures the change in voltage level due to noise has not been actively developed. In part, this is because historically the adverse effect due to noise was not that significant. However, due to demands for high speed, high integration, and low power consumption of more modern semiconductor integrated circuits, the impact of such adverse effects is much more significant.
Usually, when it is necessary to measure the change in voltage level, a converter is provided to convert a power source voltage into a digital code. In order to implement such an conversion, the driving voltage of the converter needs to be higher than the level of the power source voltage to be measured. It has been suggested that the level of the power source voltage to be measured can be reduced using a level shifter. However, conventional methods to achieve the lower source voltage levels can cause signal distortion, and are therefore not very effective.